The present invention relates to treating food to enhance fluid retention within the food during preparation of the food for immediate or subsequent consumption and during storage.
A variety of compositions and means have been employed and proposed to protect foods from effects of atmospheric oxygen and moisture, to inhibit moisture migration between components of composite foods having differing moisture contents and to "extend" and/or to improve texture and/or to improve fluid retention in foods.
Food coating compositions long have been prepared from various combinations of materials as illustratively discussed in PCT Patent Application, International Publication No. WO 86/00501, which discloses preparation of a distinct and discrete dehydrated film ply which, after preparation, is placed between components of a multi-component food product to inhibit moisture transfer between components. The film is prepared from a combination of a lipid, a cellulose-ether-carbohydrate polymer and water, although it is said that a combination of a lipid and of a starch or a protein polymer, such as albumen, could be employed. The film may be embodied by separate lipid and polymer layers, or the ingredients may be combined to form a water and oil emulsion to enable production of the film in a single ply.
Verhoef, et al., U.S. Pat. No. 4,935,251, disclose coating an at least partially baked pastry product, particularly croutons, with an oil and water emulsion which contains a film-forming material preferably rich in protein. The composition may be prepared with or without flour, and is intended to reduce moisture absorption.
Although alluding to possible applicability to various foods, Durst, U.S. Pat. No. 3,323,922, discloses coating baked goods with a combination of a film-forming substance, a plasticizer and a liquid immiscible in the plasticizer to protect the food from oxygen and effects of humidity. It is disclosed that the film-forming substances may include a variety of materials such as protein materials, including albumen, and such as gelatinized starch. The plasticizer may be water or a glycol, for example. The immiscible liquid may include oils and various organic compositions. Fillers, including non-hydrolyzed starch, may be included in the coating composition.
Bauer, et al., U.S. Pat. No. 3,406,081, disclose applying edible water-in-oil emulsions comprised of a fat, emulsifiers and water to coat a frozen meat to provide a continuous substantially water vapor-impervious coating.
Substantially fat-free food coatings also have been sought to address a lack of oil coating effectiveness of edible oil and oil-containing coatings when the coated products are heated. To address that and other problems, European Patent Application Publication No. 0 393 361 discloses coating a food with a composition which was found to be particularly useful for preventing moisture migration in a multi-component food product between food materials having differing moisture contents. As disclosed, egg, milk protein and water are mixed, coated upon a food and then heated to a temperature of from 70.degree. C. to 100.degree. C., which is disclosed to be critical, to coagulate the egg. The food upon which the composition is coated is usefully a less moist component of the composite food product.
As also disclosed by the European Application, the composition advantageously may include a gelatinized starch to improve bonding and adhesion of the egg and milk protein to the food. As disclosed, the contents of the components should not fall appreciably below or exceed limits of from 3% to 12% egg, from 3% to 18% milk protein and from 7% to 12% gelatinized starch, by weight. It is taught that if the amounts fall below these limits, the coating would be less impermeable with a less resistant texture, and that if the amounts exceed the upper limits, the coating would be too thick and too hard, and would be noticed by the consumer.
As is appreciated in the art, fluid retention and texture deterioration are problematical during preparation of so-called convenience foods which are refrigerated, and usually frozen. Fluid retention and texture deterioration are particularly problematical in the case when a food is cooked prior to being refrigerated or frozen for storage, so that the consumer need only heat the food to a temperature desirable for consumption. Because of fluid loss, a dry, fibrous, tough texture is imparted to the foods, which makes them less desirable than fresh foods to a discerning consumer.
Cooking losses incurred by meats, for example, may range up to from about 20% to about 30% by weight based upon the weight of the product prior to cooking, by reason of fluid loss during cooking. Additionally, freezing procedures, particularly procedures such as blast freezing, as is known in the art, may contribute to further fluid loss and texture deterioration. Moreover, further fluid losses may occur during storage and generally will occur upon reheating for consumption.
As also will be appreciated, further problematical are food products wherein a food, such as a meat, or vegetables, is cooked and combined with a sauce and then stored. Although the art has focused upon inhibiting moisture transfer from a more moist food component to a less moist food component of a composite food to prevent the less moist component from becoming soggy, such as in the case of a pizza, for example, the problem with combining particularly a meat with a sauce has been found to be different. Because meat, even though it could be considered a less moist component when contained in a sauce, itself contains a substantial amount of fluids, the fluids transfer out of the meat into the sauce and thereby dilute the sauce and impair the viscosity and character of the sauce, and the meat, even though contained in a fluid-containing sauce, acquires a dry, fibrous, tough character. In addition, the problem becomes even more acute when a product of this nature is retorted, as is common in the art.
Additionally, of particular recent interest in convenience food preparation is a method known as sous vide, which is employed for providing microbiologically stable vacuum packed foods, including meats, and particularly fish, which require only heating to a desirable temperature for consumption. In this process, a raw meat is placed in a pouch, preferably transparent, which then is vacuum sealed. The pouch containing the meat is heated, generally by placing it in a water bath which has a temperature of from about 60.degree. C. to about 75.degree. C. until the meat reaches an internal core temperature ("ICT") which is considered sufficient to at least make the meat microbiologically stable for storage, i.e., generally 60.degree. C. and above. Then, the meat is held at the stated temperature for about 15 mins to about 20 mins. The pouch and contents then are chilled to a refrigeration temperature, i.e., generally about 4.degree. C. to about 8.degree. C., and/or frozen.
However, when preparing products such as meat in the sous vide manner, although the objective of the process is to provide a convenience product having the appearance and characteristics of a fresh product when purchased and prepared for consumption, that objective has not been able to be realized effectively. Problems are particularly acute for fish because it loses fluids readily and becomes not only dry, fibrous and tough upon consumption, but also the product is not aesthetically pleasing in the package because of fluids which exude from the products.
One means employed to attempt to obtain a final sous vide product containing sufficient fluids and moistness has been to marinate the raw meat prior to vacuum packing it. However, on one hand, the marination tends to impart a texture to the meat which is not characteristic of conventionally cooked fresh meat, and on another hand, because the marination fluids tend to separate from the solids, the solids tend to form into a granular type consistency during the ICT cooking and during preparation for consumption.
Additionally, in the sous vide process, and for that matter in preparation of other meat or meat-containing convenience foods, it often is preferred to sear or grill the meat first to impart color to the meat to effect a desirable aesthetic effect. That, however, generally also results in a fluid loss which may range, depending upon the meat, up to about 10% by weight which, as is evident from the above discussion, contributes to a final product having a dry, fibrous, and tough texture.
Moreover, in the sous vide process or with a boil-in-bag type products, as are known also in the art, and which contain meat, for example, moisture generally separates from the meat during any preparative heating process and during storage in a further amount of from about 5% to about 15% by weight. As noted above, that presents an unappealing appearance in the package, even if an absorbent material, which is sought to be avoided, is included in the package to soak up fluids.
In addressing certain problems arguably analogous to those noted above, to prepare a "luncheon" meat product, Lindl, et al., U.S. Pat. No. 4,071,635, disclose incorporating and blending a dry composition of starch and protein components within a mass of comminuted meat to "extend" the meat. In the Lindl system, which is disclosed as also affording reduction of cooking loss, the starch component is disclosed as acting not only as a filler-extender, but also as a fat and water binder which acts within the product mass to inhibit escape of fluids from the mass. The protein is disclosed as fulfilling a texture function to improve chewability characteristics, which are said to be affected adversely by the starch.
As taught by Lindl, et al., the starch of the dry composition preferably is gelatinized corn starch, and may be employed in an amount of from 25% to 85% by dry weight based upon the weight of the dry composition. The protein, of which at least a part is egg albumen, may be employed in an amount of from 1.5% to 55% by dry weight, based upon the weight of the dry composition. The dry composition is added to the comminuted meat to be treated, and although some water may be added to the meat prior to addition of the dry composition, the majority of water is added to the meat upon addition of the dry composition. Water is employed in an amount, by weight, of from 1.5 to 4 times the weight of the dry composition, which may provide a meat to dry mix/water ratio of from 1:0.25 to 1:2.5. After mixing, the meat mixture is molded and then cooked.
To reduce cooking loss of uncomminuted whole pieces of meat, starches, including gelatinized, starches and proteins also have been disclosed as being employed as components of marination media which are sought to be impregnated within the meat mass to effect retention of fluids within the mass. Commonly, marinades are a dilute suspension of such components and may be added to whole pieces of uncomminuted meat generally by injection, as illustrated, for example, by Savage, et al., U.S. Pat. No. 3,506,455, although soaking and tumbling marination procedures to impregnate the meat also are known. As disclosed by Savage, starches and proteins are sought to be incorporated within the interior of the meat pieces in an amount of from 1% to 15% by weight of the impregnated meat. The impregnation media may include an medium, wherein it is taught that encapsulation of the starch and protein ingredients is desired to enable them to retain their water-binding capacity. A fat or oil medium also may be employed.
It also has long been practice in the convenience food preparation art to attempt to improve the appearance of foods by applying a batter, particularly flour-based batters, to the foods to enable a coating of bread crumbs or other farinaceous material to be applied on the foods for the purpose of achieving a browned appearance. Generally, the coated foods are deep-fat fried, although such may be baked. Such processes, however, have little effect upon fluid loss and, in fact, a significant problem in the art is that upon cooking for consumption, the crumb coatings become undesirably soggy. Thus, such systems do not provide guidance for one seeking to obtain a product having a fresh shelf appearance or an appearance, upon heating for consumption, which is similar to the appearance of a cooked fresh product.
An approach which is said to promote moisture retention in foods, such as cooked or raw meat or vegetables, is disclosed in UK Patent Application 2 097 646, wherein a food is coated with a substantially fat-free, flour-based batter which contains an egg white substitute which is contained in the batter in an amount of from 0.5% to 10% by weight on a dry weight basis. The egg white substitutes are disclosed as being preferably a globular proteinaceous material which is soluble in water and coagulable with heat, although such may include egg albumen "extended" with a proteinaceous or non-proteinaceous material.
Said to be a particularly preferred component of the coating composition, as set forth in the UK disclosure, is a substitute identified as MERI-WHITE, which variously is disclosed as containing an egg albumen content of up to about 28%, and starch, which includes gelatinized starch, in an amount greater than the amount of the albumen. It is disclosed that the substitutes alternatively may be based upon whey, which is said to contain about 30% lactalbumen, or upon whey protein isolates, which are said to have a protein content of between 20% and 30%.
As disclosed in the UK Application, the "typical" process employs, just as in prior art breading processes, deep-fat frying the coated food. Hence, the flour-based coating will take up cooking fat or oil which may act, in effect, as a further coating material, the coating will have a distinct, apparent browned coating, and excess frying oil must be removed from the product.